The present invention relates to an ascending/descending structure in which the pull bar can be smoothly pulled outward along the locking tube for adjustment of height without slipping off or displacement. In addition, the pull bar can be reversely pushed inward to the bottom of the locking tube for further adjustment of height.
Many kinds of appliances around us include ascending/descending structures, such as a foldable umbrella, adjustable stem of an electric fan, arm rest of a chair, etc. In various conventional ascending descending structures, several common shortcomings exist as follows:
1. Poor adjustment: The ascending/descending member is locked on a stem by a screw after each adjustment. Therefore, the screwing operation is often repeatedly performed during use of the appliances. This causes great inconvenience to a user. Moreover, with respect to a thread hole design, the screw must be first aligned with the thread hole prior to locking of the ascending/descending member. It is quite troublesome to do this. PA1 2. Poor supporting effect: By means of the screw, the ascending/descending member often can be hardly firmly locked and thus it can hardly bear any additional load. As a result, the application field of such ascending/descending structure is quite limited. PA1 1. The locking notches of the locking tube provide multiple locking stages for the pull bar so that the pull bar can be adjustably located on different heights. PA1 2. The locking pin is firmly and reliably locked the locking notch of the locking tube without slipping off. Therefore, the structure can bear greater load. PA1 3. The adjustment of the present invention is achieved by pulling/pushing movement without using any screw so that the operation is more easily performed.